Every track I tag in Picard that comes from a soundtrack gets "Soundtrack" assigned as its genre. I realize you guys might not have any control over this because folksonomy but, as the title says, "Soundtrack" is not a genre.
In Options → Options → Metadata → Folksonomy Tags there's a field called Ignore Tags.
Options → Options → Metadata → Folksonomy Tags
And 'soundtrack' is totally not a genre
Here's a related thread:
These tickets looks like the thing as well:http://tickets.musicbrainz.org/browse/MBS-3738http://tickets.musicbrainz.org/browse/MBS-8600